1. Field of the Invention
The present invention relates to a technique for selecting an optimum electronic ticket from among a plurality of electronic tickets.
2. Description of the Related Art
A technique involving the use of electronic tickets is known as a technique for preventing abuses and illegal dispositions of digital content such as image and text data.
In an example system using electronic tickets, a digital content provider delivers digital content to a user after encrypting (encapsulating) the digital content. An electronic ticket is required to decrypt the encrypted content. The electronic ticket is issued in accordance with the characteristics of the hardware such as a computer employed by the user, and is provided to the user. Consequently, use of the digital content is permitted only to a legitimate user using the computer corresponding to an electronic ticket.
Varied states of operational authority can also be given to the electronic ticket. For example, it is possible to set whether or not the authority of a printing operation or an editing operation of a digital content is given to a user. Thereby, it becomes possible to permit, for example, only the browsing of the digital content by a user and to restrict other operations.
As described above, the use electronic tickets can prevent abuse of digital content while realizing various forms of providing the content. For example, a plurality of electronic tickets may be provided with respect to one item of digital content.
When a plurality of electronic tickets effective to a certain digital content exist, conventionally a user compares the contents of the electronic tickets, and selects a desired electronic ticket. That the option of an electronic ticket is granted to a user also has an aspect of raising the degree of freedom of use of the electronic ticket. However, for example, when the aspects of operational authority vary among a plurality of electronic tickets, a user is forced to spend time and effort to select an electronic ticket while comparing the various levels or aspects of operational authority. In particular, when using a plurality of aspects of operational authority provided separately by a plurality of electronic tickets, selecting a suitable electronic ticket is complicated and, at times, difficult.
When using a plurality of aspects of operational authority provided by a plurality of electronic tickets in combination, there is a point which should be taken into consideration also from the side of the processing of the computer in which the electronic tickets are used. In the case where a digital content is used with an electronic ticket, the computer using the electronic ticket confirms whether or not the electronic ticket is effective one to the digital content, and performs the processing releasing the encapsulation of the ticket is effective. A series of such authentication processings may undesirabley create an enormous data processing burden on the computer.
Consequently, when a plurality of electronic tickets is used, it is desirable to select an electronic ticket efficient for authentication processing in a computer in addition to realizing the combination of an operation authority advantageous for a user.
Moreover, for example, when mutually different using conditions are imparted to a plurality of electronic tickets, the user is forced to select usage condition while comparing the using conditions. In particular, it is not always easy for the user to select an advantageous ticket.
For example, if a user has electronic tickets 1 and 2, the electronic ticket 1 permitting the use of two sets of content A and B without no limitations, and the electronic ticket 2 permitting the use of content sets B and C only a specified number of times, then, in the case where the user uses the electronic ticket 2 for using the content B, the value of the electronic ticket 2 decreases, and consequently the usable number of times the content C can be accessed decreases. This cannot be said to be an advantageous ticket selection for the user.